"There are people who are wired to be skeptics and there are
people who are wired to be optimists," Andreessen tells Roose.
"And I can tell you, at least from the last 20 years, if you bet
on the side of the optimists, generally you’re right."

So when he's critiquing startup ideas, Andreessen says he tries
not to ask the common question: "Will this idea work?"

Instead, he asks: "What if it does work?"

He uses his initial snubbing of eBay as an example.

"I remember when eBay came along, and I
thought, No f---ing way. A f---ing flea market? How
much crap is there in people’s garages? And who would want
all that crap?" Andreessen tells Roose. "But
that was not the relevant question. The eBay guys and the people
who invested early, they said, 'Let’s forget whether it’ll work
or not. What if it does work?' If it does work, then you’ve got a
global trading platform for the first time in the world, you’ve
got liquidity for products of all kinds, you’re going to have
true price discovery."